This chapter presents the family, school and leisure activities as the main settings for adolescent development and discusses the influences of social processes on health behaviours in these settings. The main processes are described through the social psychological constructs of social norms and social support, and observational learning, an approach informed by social cognitive theory, one of the most influential theories used in health promotion. The chapter discusses legislation and international conventions as more formalized norms. The role of such norms in promoting healthy behaviours among adolescents is demonstrated by findings from an international study on the effect of national legislation on smoking in schools. The influences of these social processes in the main developmental settings for adolescent health behaviour are analysed in terms of systems theory, particularly ecological systems theory, and the reproduction of social inequality.
Keywords: Health behaviours, social processes, settings, social norms, social support, observational learning, social cognitive theory, legislations, ecological systems theory, reproduction of social inequality, Health-behaviour in School-aged children study (HBSC).